WASHINGTON (Reuters) - U.S. President Donald Trump has postponed a speech on lowering prescription drug prices previously scheduled for Thursday to a date in the near future, the White House said on Sunday.

The White House did not provide a date or time frame for when the speech would take place, and did not say why it had been pushed back.

The address would have been Trump's first about lowering drug prices, one of the main issues he campaigned on during the 2016 presidential race.

The Republican president has said pharmaceutical companies are "getting away with murder" and has vowed to lower prescription drug prices. But the administration's proposals so far have been modest and do not go after drug companies. Congressional action on the issue is seen as unlikely.

Health and Human Services Secretary Alex Azar, who was scheduled to attend the speech, last week was hospitalized for the second time for diverticulitis, an inflammation of small pouches in the walls of the colon.

Azar was discharged from the hospital on Thursday and returned to his home state of Indiana to recover with his family, and it was unlikely he would return to Washington until sometime this week, his agency said.